Sears Holdings Corp. SHLD -9.50% said Thursday that it plans to close another 72 stores it has deemed unprofitable, as the company continues to struggle with falling sales.Sears has been closing hundreds of stores in recent years, selling brands and spinning off divisions to stay afloat as losses have mounted and as it struggles to keep its customers away from Walmart Inc., Amazon.com Inc. AMZN +0.29% and other outlets.The company said a list of the 72 stores would be posted later Thursday.